The term "opera ghost" can be replaced by several other synonyms to describe the mysterious presence that haunts operas. Some of these synonyms include "phantom of the opera", "specter in the theater", "shadowy figure", "apparition in the auditorium", and "ghostly performer". These words are often used to add a sense of drama and intrigue to stories or legends surrounding a haunted opera house. Whether it's the story of the famous Phantom of the Opera or a lesser-known tale of a ghostly musician, the opera ghost has become a popular fixture in literature and mythology.